Improvement in index-gauges and calipers



D. F. ELMER.

Index Gage and Caliper. No. 69,418. ,Patented Oct. 1,1867.

gait/eh gram. {gaunt @ftirn I). F. ELMER, OF SPRINGFIELD, MASSACHUSETTS. Letters Patent 1V0. 69,418, dated October 1, I867.

I IMPROVEMENT IN INDEX-GAUGES AND OALIPERS.

TO ALL WHOM IT MAY CONCERN:

Be it known that I, D. F. ELMER, of Springfield, in the county of II-ampdei, and State of Massachusetts, have made and invented a new and useful machine to be cal-led an Index-Gauge and Caliper; and I do hereby declare that the following is a full, clear, and exactdescription of the construction and operation of' the same, reference being had to the annexed drawings, making a part of this specification, in whieh- Figure 1 is an end elevation,

Figure 2 a side elevation, and

Figure 3 a longitudinal section.

In the manufacture of watches, jewelry, and other fine work, itis necessary for the artificer to make very nice and accurate measurement of various bodies, and to work the same to very accuratclyadjusted calipers. To facilitate such operations, I have invented an instrument which may be used either as a gauge or caliper, whereby the thirty-two hundredth part of an inch may be readily measured, which is accurate enough for all practical purposes, but which may be made to measure still more minutely if desired.

And in carrying out my invention, I construct the body thereof a hollow cylinder or tube, y, about two and one-fourth inches long by three-cighths of an inch in diameter, and onesixteenth of an inch in thickness, open at both ends, and slotted along the side from one end to within about one-fourth oi an inch of the other end; And further, I construct two boxes 0 0, half an inch, more or less, in length, and ot' a size to fit the interior or chamber of cylinder g, and to the sides of the boxes 0 o I attach by grooving or brazing or other suitable means thejaws a a, which I make about the size seen in fig. 3, and of a thickness to lit the slot in cylinder 9. I then pass box 0 into the slotted end of the cylinder, the jaw l protruding through the slot, and shove the box along till the jaw rests against the end of the slot, where I make both box and jaw fast by brazing or other" suitable means, and when so placed the end of box 0 comes within about one-eighth of an inch of the end of cylinder g, as seen in fig. 3. From jaw a I graduate the cylinder 1 along the slot therein, into thirty-seconds of an inch, (or at any desired scale,) for a distance of one inch, more or less. I then pass the box a, with jaw a "attached, into the slotted end of cylinder g, and shove the box and jaw along till they meet jaw a, and when the jaws a a are in contact with each other, the faces thereof should touch from top to bottom, or as nearly so as may be. And the box 0, with jaw (1 attached, is intended to be moved back and forth by means hereinafter specified. And furthcr,I construct a dial, 13, about one inch in diameter by one-twelfth 0f an inch in thickness, and graduate the outer edge thereof into one hundred equal parts or degrees, as seen in fig. 1. I then attach the dial B by socket and brazing or other suitable means to the end of cylinder g opposite the slot, and I make the dial B and cylinder 5/ concentric, or as nearly so as possible. And further, 1 construct a bolt, H, with a shoulder thereon near one-end, as seen in fig. and I make holt ll of a size to fit box 0, the shoulder on the bolt fitting the interior ot" cylinder The ends of bolt II I make male screws, the threads on the longer end being one thirtyrsecend of an inch apart, or as nearly so as'possible. And further, I make a small steel hand, 0, fig. 1, which I fasten to the shorter end of bolt II by means of the serrated nut c. I then insert bolt II in cylinder 51, passing it through boxes I) and 0, which latter 1 construct a female screw fitting the male screw on the longer end of bolt ll. And further, I construct a small sockcted cap, it, which I place on the slotted end of cylinder g, and on to the end of bolt II, which projects about one-fourth of an inch through cap it, I turn the small serrated nut '1', thus confining the bolt in the cylinder, but allowing it to revolve freely therein. And further, I construct the serrated heads (Z and f, which I screw on to the opposite ends ct" bolt II, till they rest firmly against the small nuts 0 and 2', and this completes the construction of my machine, which when properly adjusted allows bolt II to be revolved by either head (Z orf, and accordingly as bolt II is turned backward or forward, will jaw a approach and reccde from jaw a, and when by turning bolt II the jaws a a are brought in contact with each other, then will the hand 1: point exactly at zero on the dial ll). And when the jaws a a are'in contact, if the hand 0 assumes any other position than that indicated, it should be adjusted and brought to position, which can always and readily be done by means oi the nuts a and i. The jaws then, a a being closed or in contact, the hand 0 indicating zero on the dial I3, and the threads on the longer end of bolt II being one thirty-second of an inch apart, or the same distance as the marks of the scale on the side of cylinder g, one revolution of the bolt II will of course cause the jaw c to recede from the jaw (i one thirty-second of an inch,

as will be observed by reference to the scale on cylinder 9 and so on but the hand 0 revolves with bolt II, and marks hundredths on the dial B, bv which means I am enabled to measure the thirty-two hundredth part of an inch.

To gauge any given body by my instrument, place the body between the jaws u a, bring the jaws in contact with the opposite sides of the body, and observe the thirty-seconds of an inch indicated by thejaw a and the scale on cylinder g, and the hundredths of a thirty-second will be indicated liy the hand 0 on the dial 3. As a caliper, the jaws a a may be set at any desired distance, and any given body worked down till it passes between thejaws so set.

I prefer to have the dial B and bones 0 0 of brass, and all other parts of my instrument of steel. All the round surfaces of my instrument I turn in a lathe with great care, particularly the bolt II and the thread on the longer end thereof, and the distance between the threadson the longer end of hot II should always be onehalf as great, as great, or twice as great, as the distance between the marks of the scale on the cylindery, and this scale, as well as the dial B, should be graduated with the greatest accuracy. I serrate the edges of nuts 1' and 2', heads cZ andf, and cap 7:, for looks and convenience. The proportions of my instrument herein specified are those which I prefer, but other proportions and dimensions may be used if hought necessary or advisable.

I claim- 1. The cylinder g slotted and graduated as specified, in combination with the jaws r1 (7.", dial-plate B, hand 0, and bolt II, substantially as described.

2. The combination of the graduated dial-plate B with the cylinder in the manner and for the purpose set forth.

3. The jaws a in combination with the slotted and graduated cylinder g and bolt 11.

4. The combination of the bolt II with the graduated cylinder 7, as and for the purpose specified.

l). b. E-LUER.

Witnesses:

J. M. S'rnnnrns, SIDNEY SANnnns. 

